1. Field of the Invention
The present invention relates to a sport apparatus and, more particularly, to a ball game apparatus with which a player can enjoy training of tennis and other ball games together with factors of an electronic game.
2. Description of the Related Art
In order to train for a tennis match outside the court, a player hits a ball against a net put up with an optimal tension and continuously hits the ball returned from the net due to an elastic force of the net. Alternatively, as described in U.S. Pat. No. 4,521,016, a suspended ball tied to an elastic cord is hit against a loosely put-up net and is returned by an elastic force of the elastic cord. In a ball game apparatus described in U.S. Pat. No. 4,521,016, two vertical columns spaced apart from each other by about a distance corresponding to the width of the net stand in front of the loosely put-up net, and a ball is tied to an elastic cord suspended from the center of a horizontal frame bridged between the vertical columns to allow training for volleys. A ball is tied between elastic cords tied between the roots of the columns to train for ground strokes. However, with the above structure, the columns interfere the player, and ball positions for ground strokes are not constant, resulting in inconvenience. In particular, it is inconvenient for a handicapped player in a wheelchair to train for a tennis match because of the presence of columns.
Balls used in ball games have different sizes. The smallest ball is a golf ball and the largest ball is a soccer ball. When the tension of the net is constant, the speed of the ball returned from the net is changed in accordance with the size and weight of the ball. When a given ball is hit against the net, the speed of the ball returned from the net is changed in accordance with a change in tension of the net. Therefore, in order to optimally train for a ball game, the tension of the net must be appropriately adjusted. In a conventional ball game apparatus, the tension of the net is predetermined or a large number of strings tied at four corners and sides of the net must be tightened or loosened. Strong demand has arisen for allowing simple adjustment of a tension of a net in accordance with the type of ball and a desired speed of the ball returned from the net.
In another conventional ball game apparatus, a target is attached to the center of a tennis training net, and the player hits a ball toward the target. In this case, the player can know only whether the ball is hit against the target. For example, the ball speed which is the most important factor particularly in a tennis game cannot be measured.
Various conventional ball game apparatuses provide only monotonous training contents and are not interesting. Therefore, demand has arisen for a ball game apparatus which allows the player to enjoy training for a long period of time without loss of interest.